Compressed-air locomotive.



PATENTED NOV. 15, 1904.

W. R. PRATT.

COMPRESSED AIR LOCOMOTIVE.

APPLICATION FILED OCT. 8, 1901.

N0 MODEL.

Patented November 15, 1904.

PATENT OFFICE.

WILSON R. PRATT, OF TOPEKA, KANSAS.

COMPRESSED-AIR LOCOMOTIVE.

SPECIFICATION forming part of Letters Patent No. 774,778, dated November15, 1904.

Application filed October 8, 1901. Serial No. 77,942. (No inodel.)

To all whom it may concern.-

Be it known that I, WILsoN R. PRATT, a citizen of the United States,residing at Topeka, in the county of Shawnee and State of Kansas, haveinvented certain new and useful Improvements in Compressed-AirLocomotives; and I do declare the following to be a full, clear, andexact description of the invention, such as will enable others skilledin the art to which it appertains to make and use the same, referencebeing had to the accompanying drawings, and t0 the letters of referencemarked thereon, which form a partof this specification.

My invention relates to improvements in compressed-air locomotives inwhich a portion of the air is stored at high pressure; and

the object of my invention is to utilize the dif-' ferences between thehigh pressure and the low pressure to which it is reduced for use in thecompression offree air and also to add to the units of energy containedin the air in its compressed form by heating the same at the immediatepoint of consumption.

I attain these objects by the mechanical devices illustrated in theaccompanying drawings, in which- Figure l is represented as a sideelevation of the locomotive. Fig. 2 is a plan View of same. Fig. 3 is asection taken through the line a f Fig. 4; and Fig. 4 is an enlargedsection of the heater, taken through the line 0 d of Fig. 3, the samebeing considered as a plan View for this purpose.

Similar letters refer to similar parts throughout the several views.

In the views given of the engine and tender I have simply outlined thoseparts in common use.

In my device the Water-tank and coal-bin of the tender in common use arereplaced by a high-pressure air-tank A and the free-air compressors Cand-C, having suitable driving-motors B and B, and in the engine properthe boiler is replaced by a secondary air-tank D and a heater E. As willbe seen, the aircompressors are not specialized, this being also true ofthe heater, as in the forms devised for the special service required ofthem ors, it should be capable of sustaining pressure of seven hundredand fifty pounds per square inch. The air compressors C C shouldlikewise be capable of sustaining pressure of about seven hundred andfifty pounds. The secondary reservoir D should be capable of sustainingpressure of about three hundred and fifty pounds per square inch, asalso the heater E. The strength of the various pipes and fittings shouldbe in harmony as to strengths with the reservoirs to which they areattached or connected.

The engine B of the first air-compressor is directly connected with theair-reservoir A by the conduit-pipe I. This connecting-pipe ispreferably, as shown, without a stop-cock. The said pipe I heads directto the valve-chest of the said engine B andthrough said valves to thecylinder. The exhaust of the first cylinder is through the pipe I, whichleads direct to the valve-chest of the second engine B and through thevalves of the said engine B to the cylinder of same, as in the firstengine. The exhaust of this second engine passesthrough the pipe K andthe hose S into the secondary reservoir D. Leading from the front end ofthis reservoir is the pipe L, with its stop-cock L, controlled andoperated by the lever M, the said pipe L connecting the air-tank D withthe heater E.

The air-compressor cylinders C and C have pipes N N and O O, thatconnect with the valve-chambers in said cylinders and lead the aircompressed therein, via the conduit-pipe P, hose S, and'theconnecting-pipe P, direct to the heater E.

On each side of the reservoir D are the gasolene or crude-oil tanks G,that connect, through the feed-pipes RR, with the burners S (see Fig. 4)of the fire-box F of the heater E, which is set with the vertical fiuesT.

In operation my invention works as follows:

The tank A is filled with compressed air, say at, five hundred poundspressure, this pressure varying according to the number of free-aircompressors used in the combination and the number of pounds pressurerequired to run the engines of the locomotive. With twoaircompressors,as shown,and the heater-pressure set at one hundred andfifty pounds the tank A should contain air compressed to about fivehundred pounds pressure. This pressure of the primary reservoir wouldcall for air at about two hundred pounds pressure in the secondaryreservoir D and at about one hundred pounds pressure in the heater E.The air being stored in the various reservoirs in the proportions named,a fire is started in the fire-box F. On the opening of the throttlevalveU the compressed air will be admitted to the cylinders H via the pipes VY, and the pressure in the heater is of necessity reduced. Thisreduction of pressure in the heater E is compensated for by admittingair into the said heater from the secondary tank D by the opening of thevalve L by the engineer in charge. Upon reduction of the pressure in thetank D the engines B B are operated by the expansive force of thecompressed air of the tank A, which passes therethrough direct to thebank D to establish equilibrium of pressures throughout the apparatus.The

passing of this air by operating the engines works the air-compressors Cand C, and the free air compressed thereby is conducted through theconduit-pipe P, connecting-hose S, and pipe P into the heater E. Thisair from the compressors serves to economize the use of the air from thetank A, and it flows into the heater E until the back pressure from theheater overcomes the force thereof, whereupon the air-compressors stopworking, and the engines being checked in their movement no further flowof compressed air takes place between the tanks A and D. When the valveL is opened to introduce compressed air from D to the heater E, theoperation above described is repeated, the air from tank A resupplyingtank D and the free air compressed by the air-compressors being led tothe heater 1]. This operation will continue to be carried on as long asthere is enough pressure in the reservoir-tank A to overcome theresistance of the air-compressors C C and operate the engines B B.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

The combination with a locomotive-engine and tank, of a compressed-airtank on the tender, air engines and compressors driven thereby also onthe tender, a second tank on the locomotive-engine taking the exhaustfrom the air-engines, a heater also on the locomotive-engine receivingair from the compressor and from the second tank and delivery-pipe fromthe heater to the driving-cylinder of the locomotive-engine.

In testimony whereof I affix my signature in the presence of twowitnesses.

WILSON R. PRATT. Witnesses:

EDNA F. PRESCOTT, W. F. SoHooH.

